Rockwell Automation 20-COMM-R Remote I/O Adapter - Manual (Page 66)

5-8 Using Block Transfer Messaging
20-COMM-R Remote I/O Adapter User Manual
Publication 20COMM-UM004D-EN-P
Ladder Logic Program
Figure 5.3 ControlLogix Example Ladder Logic for Block Transfer Messaging
Tag Name Type
SendMessageRequest BOOL
SendMessageRequestOneShot BOOL
PerformingMessagingRequest BOOL
MessagingRequestError BOOL
The20CommR:I AB:RIO_4IOGROUP:I:0
MsgBlockTransferWrite MESSAGE
MsgBlockTransferRead MESSAGE
0 Copy File
Source The20CommR:I.Data[0]
Dest BlockTransferStatus
Length 1
COP
Make a local copy of the block transfer status word to avoid it changing mid-scan.
1
SendMessageRequest
ONS
SendMessageRequestOneShot
L
PerformMessagingRequest
U
MessagingRequestError
When the user enables the SendMessageRequest tag, start the message logic.
2
PerformMessagingRequest BlockTransferStatus.9
/
BlockTransferStatus.10
EN
DN
ER
Type - Block Transfer Write
Message Control MsgBlockTransferWrite ...
MSG
When requested (and the 20-COMM-R is ready), send the messaging request to the drive.
3
PerformMessagingRequest BlockTransferStatus.10
EN
DN
ER
Type - Block Transfer Read
Message Control MsgBlockTransferRead ...
MSG
Pick up the messaging response from the drive.
4
PerformMessagingRequest MsgBlockTransferRead.DN
U
PerformMessagingRequest
Once the response is complete, end the messaging transaction.
5
PerformMessagingRequest BlockTransferStatus.11
L
MessagingRequestError
U
PerformMessagingRequest
If a messaging error occurs, end the transaction and indicate the error.
(End)